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$\begingroup$Although this question is technically a duplicate, I like this way of asking the question, as it is much easier imagining the mixing of wine and water than picturing the mixing and shaking up of two different sand colors.$\endgroup$
– IQAndreasOct 27 '14 at 13:30

$\begingroup$@IQAndreas, this way it has second answer, since there is always water in a "pure" wine.$\endgroup$
– klm123Oct 29 '14 at 8:22

1 Answer
1

Counter-intuitively, there are exactly equal amounts. We can see this if we consider that each glass has lost and gained the same amount of liquid (a spoonful), so any loss to the other glass is precisely offset by gain from that glass.

Unless, of course, the "filled with water/wine" statements were to be taken literally, in which case the water glass will have more wine because the wine glass lost some when it overflowed.

$\begingroup$And a drop of liquid will certainly remain on the spoon. Mostly wine.$\endgroup$
– Florian FOct 27 '14 at 9:51

$\begingroup$We can dodge that by noting the spoon was never specifically removed. ;-)$\endgroup$
– frodoskywalkerOct 27 '14 at 10:11

$\begingroup$If we want to get really silly, we'll note that the surface tension of water is higher than that of wine so the spoonful of water would contain more liquid than the spoonful of wine.$\endgroup$
– frodoskywalkerOct 27 '14 at 10:16